gproc_dist_tests.erl

%% ``The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved via the world wide web at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
%% AB. All Rights Reserved.''
%%
%% @author Ulf Wiger <ulf.wiger@erlang-solutions.com>
%%
-module(gproc_dist_tests).

-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-export([t_spawn/1, t_spawn_reg/2]).

dist_test_() ->
    {timeout, 120,
     [{setup,
       fun() ->
	       Ns = start_slaves([dist_test_n1, dist_test_n2]),
	       ?assertMatch({[ok,ok],[]},
			    rpc:multicall(Ns, application, set_env,
					  [gproc, gproc_dist, Ns])),
	       ?assertMatch({[ok,ok],[]},
			    rpc:multicall(Ns, application, start, [gproc])),
	       Ns
       end,
       fun(Ns) ->
	       [rpc:call(N, init, stop, []) || N <- Ns]
       end,
       fun(Ns) ->
	       {inorder,
		[
		 {inparallel, [
			       fun() ->
			       	       ?debugVal(t_simple_reg(Ns))
			       end,
			       fun() ->
			       	       ?debugVal(t_simple_reg_or_locate(Ns))
			       end,
			       fun() ->
			       	       ?debugVal(t_simple_counter(Ns))
			       end,
			       fun() ->
			       	       ?debugVal(t_aggr_counter(Ns))
			       end,
			       fun() ->
			       	       ?debugVal(t_update_counters(Ns))
			       end,
			       fun() ->
			       	       ?debugVal(t_shared_counter(Ns))
			       end,
			       fun() ->
			       	       ?debugVal(t_mreg(Ns))
			       end,
			       fun() ->
			       	       ?debugVal(t_await_reg(Ns))
			       end,
			       fun() ->
			       	       ?debugVal(t_await_self(Ns))
			       end,
			       fun() ->
			       	       ?debugVal(t_await_reg_exists(Ns))
			       end,
			       fun() ->
				       ?debugVal(t_give_away(Ns))
			       end,
			       fun() ->
				       ?debugVal(t_sync(Ns))
			       end,
			       fun() ->
				       ?debugVal(t_monitor(Ns))
			       end,
			       fun() ->
				       ?debugVal(t_subscribe(Ns))
			       end
			      ]
		 },
		 fun() ->
			 ?debugVal(t_sync_cand_dies(Ns))
		 end,
		 {timeout, 90, [fun() ->
		 			?debugVal(t_fail_node(Ns))
		 		end]}
		]}
       end
      }]}.

-define(T_NAME, {n, g, {?MODULE, ?LINE}}).
-define(T_KVL, [{foo, "foo"}, {bar, "bar"}]).
-define(T_COUNTER, {c, g, {?MODULE, ?LINE}}).

t_simple_reg([H|_] = Ns) ->
    Name = ?T_NAME,
    P = t_spawn_reg(H, Name),
    ?assertMatch(ok, t_lookup_everywhere(Name, Ns, P)),
    ?assertMatch(true, t_call(P, {apply, gproc, unreg, [Name]})),
    ?assertMatch(ok, t_lookup_everywhere(Name, Ns, undefined)),
    ?assertMatch(ok, t_call(P, die)).

t_simple_reg_or_locate([A,B|_] = _Ns) ->
    Name = ?T_NAME,
    P1 = t_spawn(A),
    _Ref = erlang:monitor(process, P1),
    ?assertMatch({P1, the_value},
		 t_call(P1, {apply, gproc, reg_or_locate, [Name, the_value]})),
    P2 = t_spawn(B),
    _Ref2 = erlang:monitor(process, P2),
    ?assertMatch({P1, the_value},
		 t_call(P2, {apply, gproc, reg_or_locate, [Name, other_value]})),
    ?assertMatch(ok, t_call(P1, die)),
    ?assertMatch(ok, t_call(P2, die)).


t_simple_counter([H|_] = Ns) ->
    Ctr = ?T_COUNTER,
    P = t_spawn_reg(H, Ctr, 3),
    ?assertMatch(ok, t_read_everywhere(Ctr, P, Ns, 3)),
    ?assertMatch(5, t_call(P, {apply, gproc, update_counter, [Ctr, 2]})),
    ?assertMatch(ok, t_read_everywhere(Ctr, P, Ns, 5)),
    ?assertMatch(ok, t_call(P, die)).

t_shared_counter([H|_] = Ns) ->
    Ctr = ?T_COUNTER,
    P = t_spawn_reg_shared(H, Ctr, 3),
    ?assertMatch(ok, t_read_everywhere(Ctr, shared, Ns, 3)),
    ?assertMatch(5, t_call(P, {apply, gproc, update_shared_counter, [Ctr, 2]})),
    ?assertMatch(ok, t_read_everywhere(Ctr, shared, Ns, 5)),
    ?assertMatch(ok, t_call(P, die)),
    ?assertMatch(ok, t_read_everywhere(Ctr, shared, Ns, 5)),
    ?assertMatch(ok, t_read_everywhere(Ctr, shared, Ns, 5)), % twice
    P1 = t_spawn(H),
    ?assertMatch(true, t_call(P1, {apply, gproc, unreg_shared, [Ctr]})),
    ?assertMatch(ok, t_read_everywhere(Ctr, shared, Ns, badarg)).


t_aggr_counter([H1,H2|_] = Ns) ->
    {c,g,Nm} = Ctr = ?T_COUNTER,
    Aggr = {a,g,Nm},
    Pc1 = t_spawn_reg(H1, Ctr, 3),
    Pa = t_spawn_reg(H2, Aggr),
    ?assertMatch(ok, t_read_everywhere(Ctr, Pc1, Ns, 3)),
    ?assertMatch(ok, t_read_everywhere(Aggr, Pa, Ns, 3)),
    Pc2 = t_spawn_reg(H2, Ctr, 3),
    ?assertMatch(ok, t_read_everywhere(Ctr, Pc2, Ns, 3)),
    ?assertMatch(ok, t_read_everywhere(Aggr, Pa, Ns, 6)),
    ?assertMatch(5, t_call(Pc1, {apply, gproc, update_counter, [Ctr, 2]})),
    ?assertMatch(ok, t_read_everywhere(Ctr, Pc1, Ns, 5)),
    ?assertMatch(ok, t_read_everywhere(Aggr, Pa, Ns, 8)),
    ?assertMatch(ok, t_call(Pc1, die)),
    ?assertMatch(ok, t_read_everywhere(Aggr, Pa, Ns, 3)),
    ?assertMatch(ok, t_call(Pc2, die)),
    ?assertMatch(ok, t_call(Pa, die)).

t_update_counters([H1,H2|_] = Ns) ->
    {c,g,N1} = C1 = ?T_COUNTER,
    A1 = {a,g,N1},
    C2 = ?T_COUNTER,
    P1 = t_spawn_reg(H1, C1, 2),
    P12 = t_spawn_reg(H2, C1, 2),
    P2 = t_spawn_reg(H2, C2, 1),
    Pa1 = t_spawn_reg(H2, A1),
    ?assertMatch(ok, t_read_everywhere(C1, P1, Ns, 2)),
    ?assertMatch(ok, t_read_everywhere(C1, P12, Ns, 2)),
    ?assertMatch(ok, t_read_everywhere(C2, P2, Ns, 1)),
    ?assertMatch(ok, t_read_everywhere(A1, Pa1, Ns, 4)),
    ?debugFmt("code:which(gproc_dist) = ~p~n", [code:which(gproc_dist)]),
    ?assertMatch([{C1,P1, 3},
		  {C1,P12,4},
		  {C2,P2, 0}], t_call(P1, {apply, gproc, update_counters,
					   [g, [{C1,P1,1},{C1,P12,2},{C2,P2,{-2,0,0}}]]})),
    ?assertMatch(ok, t_read_everywhere(C1, P1, Ns, 3)),
    ?assertMatch(ok, t_read_everywhere(C1, P12, Ns, 4)),
    ?assertMatch(ok, t_read_everywhere(C2, P2, Ns, 0)),
    ?assertMatch(ok, t_read_everywhere(A1, Pa1, Ns, 7)),
    ?assertMatch(ok, t_call(P1, die)),
    ?assertMatch(ok, t_call(P12, die)),
    ?assertMatch(ok, t_call(P2, die)).


t_mreg([H|_] = Ns) ->
    Kvl = ?T_KVL,
    Keys = [K || {K,_} <- Kvl],
    P = t_spawn_mreg(H, Kvl),
    [?assertMatch(ok, t_lookup_everywhere({n,g,K}, Ns, P)) || K <- Keys],
    ?assertMatch(true, t_call(P, {apply, gproc, munreg, [n, g, Keys]})),
    [?assertMatch(ok, t_lookup_everywhere({n,g,K},Ns,undefined)) || K <- Keys],
    ?assertMatch(ok, t_call(P, die)).

t_await_reg([A,B|_]) ->
    Name = ?T_NAME,
    P = t_spawn(A),
    Ref = erlang:monitor(process, P),
    P ! {self(), Ref, {apply, gproc, await, [Name]}},
    t_sleep(),
    P1 = t_spawn_reg(B, Name),
    ?assert(P1 == receive
		      {P, Ref, Res} ->
			  element(1, Res);
		      {'DOWN', Ref, _, _, Reason} ->
			  erlang:error(Reason);
		      Other ->
			  erlang:error({received,Other})
		  end),
    ?assertMatch(ok, t_call(P, die)),
    ?assertMatch(ok, t_call(P1, die)).

t_await_self([A|_]) ->
    Name = ?T_NAME,
    P = t_spawn(A, false),  % don't buffer unknowns
    Ref = t_call(P, {apply, gproc, nb_wait, [Name]}),
    ?assertMatch(ok, t_call(P, {selective, true})),
    ?assertMatch(true, t_call(P, {apply, gproc, reg, [Name, some_value]})),
    ?assertMatch({registered, {Name, P, some_value}},
		 t_call(P, {apply_fun, fun() ->
					       receive
						   {gproc, Ref, R, Wh} ->
						       {R, Wh}
					       after 10000 ->
						       timeout
					       end
				       end})),
    ?assertMatch(ok, t_call(P, {selective, false})),
    ?assertMatch(true, t_call(P, {apply, gproc, unreg, [Name]})).

t_await_reg_exists([A,B|_]) ->
    Name = ?T_NAME,
    P = t_spawn(A),
    Ref = erlang:monitor(process, P),
    P1 = t_spawn_reg(B, Name),
    P ! {self(), Ref, {apply, gproc, await, [Name]}},
    ?assert(P1 == receive
		      {P, Ref, Res} ->
			  element(1, Res);
		      {'DOWN', Ref, _, _, Reason} ->
			  erlang:error(Reason);
		      Other ->
			  erlang:error({received,Other})
		  end),
    ?assertMatch(ok, t_call(P, die)),
    ?assertMatch(ok, t_call(P1, die)).

t_give_away([A,B|_] = Ns) ->
    Na = ?T_NAME,
    Nb = ?T_NAME,
    Pa = t_spawn_reg(A, Na),
    Pb = t_spawn_reg(B, Nb),
    ?assertMatch(ok, t_lookup_everywhere(Na, Ns, Pa)),
    ?assertMatch(ok, t_lookup_everywhere(Nb, Ns, Pb)),
    ?assertMatch(Pb, t_call(Pa, {apply, gproc, give_away, [Na, Nb]})),
    ?assertMatch(ok, t_lookup_everywhere(Na, Ns, Pb)),
    ?assertMatch(Pa, t_call(Pb, {apply, gproc, give_away, [Na, Pa]})),
    ?assertMatch(ok, t_lookup_everywhere(Na, Ns, Pa)),
    ?assertMatch(ok, t_call(Pa, die)),
    ?assertMatch(ok, t_call(Pb, die)).

t_sync(Ns) ->
    %% Don't really know how to test this...
    [?assertMatch(true, rpc:call(N, gproc_dist, sync, []))
     || N <- Ns].

t_monitor([A,B|_]) ->
    Na = ?T_NAME,
    Pa = t_spawn_reg(A, Na),
    Pb = t_spawn(B, _Selective = true),
    Ref = t_call(Pb, {apply, gproc, monitor, [Na]}),
    ?assert(is_reference(Ref)),
    ?assertMatch(ok, t_call(Pa, die)),
    ?assertMatch({gproc,unreg,Ref,Na}, got_msg(Pb, gproc)),
    Pc = t_spawn_reg(A, Na),
    Ref1 = t_call(Pb, {apply, gproc, monitor, [Na]}),
    ?assertMatch(true, t_call(Pc, {apply, gproc, unreg, [Na]})),
    ?assertMatch({gproc,unreg,Ref1,Na}, got_msg(Pb, gproc)).

t_subscribe([A,B|_] = Ns) ->
    Na = ?T_NAME,
    Pb = t_spawn(B, _Selective = true),
    ?assertEqual(ok, t_call(Pb, {apply, gproc_monitor, subscribe, [Na]})),
    ?assertMatch({gproc_monitor, Na, undefined}, got_msg(Pb, gproc_monitor)),
    Pa = t_spawn_reg(A, Na),
    ?assertMatch({gproc_monitor, Na, Pa}, got_msg(Pb, gproc_monitor)),
    Pc = t_spawn(A),
    t_call(Pa, {apply, gproc, give_away, [Na, Pc]}),
    ?assertMatch(ok, t_lookup_everywhere(Na, Ns, Pc)),
    ?assertEqual({gproc_monitor,Na,{migrated,Pc}}, got_msg(Pb, gproc_monitor)),
    ?assertEqual(ok, t_call(Pc, die)),
    ?assertEqual({gproc_monitor,Na,undefined}, got_msg(Pb, gproc_monitor)).

got_msg(Pb, Tag) ->
    t_call(Pb,
	   {apply_fun,
	    fun() ->
		    receive
			M when element(1, M) == Tag ->
			    M
		    after 1000 ->
			    timeout
		    end
	    end}).

%% Verify that the gproc_dist:sync() call returns true even if a candidate dies
%% while the sync is underway. This test makes use of sys:suspend() to ensure that
%% the other candidate doesn't respond too quickly.
t_sync_cand_dies([A,B|_]) ->
    Leader = rpc:call(A, gproc_dist, get_leader, []),
    Other = case Leader of
		A -> B;
		B -> A
	    end,
    ?assertMatch(ok, rpc:call(Other, sys, suspend, [gproc_dist])),
    P = rpc:call(Other, erlang, whereis, [gproc_dist]),
    Key = rpc:async_call(Leader, gproc_dist, sync, []),
    %% The overall timeout for gproc_dist:sync() is 5 seconds. Here, we should
    %% still be waiting.
    ?assertMatch(timeout, rpc:nb_yield(Key, 1000)),
    exit(P, kill),
    %% The leader should detect that the other candidate died and respond
    %% immediately. Therefore, we should have our answer well within 1 sec.
    ?assertMatch({value, true}, rpc:nb_yield(Key, 1000)).

t_fail_node([A,B|_] = Ns) ->
    Na = ?T_NAME,
    Nb = ?T_NAME,
    Pa = t_spawn_reg(A, Na),
    Pb = t_spawn_reg(B, Nb),
    ?assertMatch(ok, rpc:call(A, application, stop, [gproc])),
    ?assertMatch(ok, t_lookup_everywhere(Na, Ns -- [A], undefined)),
    ?assertMatch(ok, t_lookup_everywhere(Nb, Ns -- [A], Pb)),
    ?assertMatch(ok, rpc:call(A, application, start, [gproc])),
    ?assertMatch(ok, t_lookup_everywhere(Na, Ns, undefined)),
    ?assertMatch(ok, t_lookup_everywhere(Nb, Ns, Pb)),
    ?assertMatch(ok, t_call(Pa, die)),
    ?assertMatch(ok, t_call(Pb, die)).

t_sleep() ->
    timer:sleep(500).

t_lookup_everywhere(Key, Nodes, Exp) ->
    t_lookup_everywhere(Key, Nodes, Exp, 3).

t_lookup_everywhere(Key, _, Exp, 0) ->
    {lookup_failed, Key, Exp};
t_lookup_everywhere(Key, Nodes, Exp, I) ->
    Expected = [{N, Exp} || N <- Nodes],
    Found = [{N,rpc:call(N, gproc, where, [Key])} || N <- Nodes],
    if Expected =/= Found ->
	    ?debugFmt("lookup ~p failed~n"
		      "(Expected: ~p;~n"
		      " Found   : ~p), retrying...~n",
		      [Key, Expected, Found]),
	    t_sleep(),
	    t_lookup_everywhere(Key, Nodes, Exp, I-1);
       true ->
	    ok
    end.

t_read_everywhere(Key, Pid, Nodes, Exp) ->
    t_read_everywhere(Key, Pid, Nodes, Exp, 3).

t_read_everywhere(Key, _, _, Exp, 0) ->
    {read_failed, Key, Exp};
t_read_everywhere(Key, Pid, Nodes, Exp, I) ->
    Expected = [{N, Exp} || N <- Nodes],
    Found = [{N, read_result(rpc:call(N, gproc, get_value, [Key, Pid]))}
	     || N <- Nodes],
    if Expected =/= Found ->
	    ?debugFmt("read ~p failed~n"
		      "(Expected: ~p;~n"
		      " Found   : ~p), retrying...~n",
		      [{Key, Pid}, Expected, Found]),
	    t_sleep(),
	    t_read_everywhere(Key, Pid, Nodes, Exp, I-1);
       true ->
	    ok
    end.

read_result({badrpc, {'EXIT', {badarg, _}}}) -> badarg;
read_result(R) -> R.

t_spawn(Node) ->
    t_spawn(Node, false).

t_spawn(Node, Selective) when is_boolean(Selective) ->
    Me = self(),
    P = spawn(Node, fun() ->
			    Me ! {self(), ok},
			    t_loop(Selective)
		    end),
    receive
	{P, ok} -> P
    end.

t_spawn_reg(Node, Name) ->
    t_spawn_reg(Node, Name, default_value(Name)).

t_spawn_reg(Node, Name, Value) ->
    Me = self(),
    spawn(Node, fun() ->
			?assertMatch(true, gproc:reg(Name, Value)),
			Me ! {self(), ok},
			t_loop()
		end),
    receive
	{P, ok} -> P
    end.

t_spawn_reg_shared(Node, Name, Value) ->
    Me = self(),
    spawn(Node, fun() ->
			?assertMatch(true, gproc:reg_shared(Name, Value)),
			Me ! {self(), ok},
			t_loop()
		end),
    receive
	{P, ok} -> P
    end.

default_value({c,_,_}) -> 0;
default_value(_) -> undefined.

t_spawn_mreg(Node, KVL) ->
    Me = self(),
    spawn(Node, fun() ->
			?assertMatch(true, gproc:mreg(n, g, KVL)),
			Me ! {self(), ok},
			t_loop()
		end),
    receive
	{P, ok} -> P
    end.

t_call(P, Req) ->
    Ref = erlang:monitor(process, P),
    P ! {self(), Ref, Req},
    receive
	{P, Ref, Res} ->
	    erlang:demonitor(Ref),
	    Res;
	{'DOWN', Ref, _, _, Error} ->
	    erlang:error({'DOWN', P, Error})
    end.

t_loop() ->
    t_loop(false).

t_loop(Selective) when is_boolean(Selective) ->
    receive
	{From, Ref, die} ->
	    From ! {self(), Ref, ok};
	{From, Ref, {selective, Bool}} when is_boolean(Bool) ->
	    From ! {self(), Ref, ok},
	    t_loop(Bool);
	{From, Ref, {apply, M, F, A}} ->
	    From ! {self(), Ref, apply(M, F, A)},
	    t_loop(Selective);
	{From, Ref, {apply_fun, F}} ->
	    From ! {self(), Ref, F()},
	    t_loop(Selective);
	Other when not Selective ->
	    ?debugFmt("got unknown msg: ~p~n", [Other]),
	    exit({unknown_msg, Other})
    end.

start_slaves(Ns) ->
    [H|T] = Nodes = [start_slave(N) || N <- Ns],
    _ = [rpc:call(H, net_adm, ping, [N]) || N <- T],
    Nodes.

start_slave(Name) ->
    case node() of
        nonode@nohost ->
            os:cmd("epmd -daemon"),
            {ok, _} = net_kernel:start([gproc_master, shortnames]);
        _ ->
            ok
    end,
    {Pa, Pz} = paths(),
    Paths = "-pa ./ -pz ../ebin" ++
        lists:flatten([[" -pa " ++ Path || Path <- Pa],
		       [" -pz " ++ Path || Path <- Pz]]),
    {ok, Node} = slave:start(host(), Name, Paths),
    %% io:fwrite(user, "Slave node: ~p~n", [Node]),
    Node.

paths() ->
    Path = code:get_path(),
    {ok, [[Root]]} = init:get_argument(root),
    {Pas, Rest} = lists:splitwith(fun(P) ->
					  not lists:prefix(Root, P)
				  end, Path),
    {_, Pzs} = lists:splitwith(fun(P) ->
				       lists:prefix(Root, P)
			       end, Rest),
    {Pas, Pzs}.


host() ->
    [_Name, Host] = re:split(atom_to_list(node()), "@", [{return, list}]),
    list_to_atom(Host).

-endif.